In this work cobalt oxide nanoparticles were introduced for preparation of a novel solid phase
microextraction (SPME) fiber coating. Chemical bath deposition (CBD) technique was used in order for
synthesis and immobilization of the Co3O4 nanomaterials on a Pt wire for fabrication of SPME fiber. The
prepared cobalt oxide coating was characterized by scanning electron microscopy (SEM) and X-ray
diffraction (XRD) analysis. The fiber was evaluated for the extraction of benzene, toluene, ethylbenzene
and xylene (BTEX) in combination with GC–MS. A simplex optimization methodwas used to optimize the
factors affecting the extraction efficiency. Under optimized conditions, the proposed fiber showed
extraction efficiencies comparable to those of a commercial polydimethylsiloxane (PDMS) fiber toward
the BTEX compounds. The repeatability of the fiber and its reproducibility, expressed as relative standard
deviation (RSD), were lower than about 11%. No significant change was observed in the extraction
efficiency of the new SPME fiber after over 50 extractions. The fiber was successfully applied to the
determination of BTEX compounds in real samples. The proposed nanostructure cobalt oxide fiber is a
promising alternative to the commercial fibers as it is robust, inexpensive and easily prepared.